Hudson Journal; Where Daylight's a Risk, Dark Is a Time to Shine

As wisps of cloud drifted across a half moon, 9-year-old Mary Begg, in helmet and harness, climbed the 10 rungs of a ladder toward the lowest foot grips on a soaring climbing wall.

Hesitating a moment, Mary, a shy girl with owlish glasses, reached up and touched a toehold with her hand before rappelling off the wall, eliciting a cheer from her fellow campers below.

As youngsters in countless other camps were singing their final song of the night and tucking themselves into bunk beds, the young (and not so young) participants in Camp Sundown here were just starting their day.

The camp is intended to give a high-energy, outdoor camp experience to those with a rare genetic disorder, xeroderma pigmentosum, which makes them unable to tolerate ultraviolet light. And so activities like this one, on a rugged adventure course at Columbia-Greene Community College, take place at night, when the campers can venture safely outside.

Under the eerie glow of eight 1,000-watt bulbs hovering overhead on stanchions, Mary -- who had traveled all the way from Australia -- and the others tackled a network of poles, ropes, pulleys and other contraptions that looked like something out of the television show ''Fear Factor.''

Most participants were from the United States, but another young girl had come from Morocco, while the oldest camper, Betty Wallace, 62, had arrived from Manchester, England. Because xeroderma pigmentosum afflicts only one in a million people, sufferers can feel tremendous isolation at home, even torment. The camp gives them, and their families, a chance to share experiences and information and to feel less alone.

''Here, she's normal,'' said Mary's mother, Lynda Begg, who, with her husband, Jules, spent $8,000 on the air fare. ''She's one of the kids in camp. Everybody else has to look out for the same difficulties, whereas at home she's always the different one.''

Now in its seventh year, Camp Sundown is a charitable organization founded by Dan and Caren Mahar of Craryville, N.Y., whose 10-year-old daughter, Katie, has the disorder, also known as X.P. This year, the 20 campers and their families stayed in Poughkeepsie, N.Y., but a permanent camp building, now under construction in Craryville, should be completed by this fall.

One of several institutions in the Hudson Valley that have rallied to the camp's cause, the college allowed the campers use of the adventure course and provided the instructors free. It even rented the lights.

Many campers had masses of freckles covering their face and body. Others, like Rafael Figuero, a 25-year-old computer technician from St. Louis, had severe scarring from the removal of lesions and cancerous tumors, in his case hundreds of them. X.P. sufferers are 1,000 times as likely to develop skin cancers as other people. Even brief exposures to the sun can cause instant blistering.

Some, like Alixe Johnson, a 14-year-old girl from Greensboro, N.C., live in houses, ride in cars and attend schools, all with special film covering the windows to block ultraviolet light. They slather on sun block four times a day, cover up completely for a sprint from house to car, or don't go out at all during the day. They wait for night, when they are finally free.

''On a typical day, she might be in the sun for 45 seconds to a minute, if you add it all up,'' said Neil Johnson, Alixe's father, who had just walked across a cable 20 feet off the ground that resembled a tightrope while she looked on. ''When the sun goes down, she's out the door.''

Alixe, soft-spoken with honey-colored hair and porcelain skin, had just dismounted the centipede, a wishbone-shaped structure the size of a house with small pegs for climbing. ''Oh my God,'' she gasped as she touched the ground, clearly elated. An old camp friend, another teenager with X.P., came over and gave her a silent, congratulatory embrace.

Attending Camp Sundown for the seventh summer in a row, Alixe has grown up with the other campers, and they stay in touch during the year. Alixe does not know of a single other person with the condition in North Carolina.

''When you're here, it doesn't seem like you're allergic to the sun,'' she said. ''You're going out and doing stuff until 4 in the morning and having a good time.''

But for families who had come from a great distance, who had never before seen New York, the question of how much to let their children experience beyond the four nights of camp weighed heavily. ''Every time Mary goes out in the sun, there's a little bit of damage, and it accumulates,'' said her father, Dr. Begg, a psychiatrist.

With camp ending today, the Beggs planned to take Mary to see the Statue of Liberty. It would be an outing fraught with risk. ''How do we juggle her quality of life with protecting her from the sun?'' asked Dr. Begg as moths flitted across the illuminated sky. ''That's our dilemma. This camp, the people here, understand that.''